Ten-year outcomes of high-dose intensity-modulated radiation therapy for nonmetastatic prostate cancer with unfavorable risk: early initiation of salvage therapy may replace long-term adjuvant androgen deprivation

• Published in: International journal of clinical oncology Vol. 24; no. 10; pp. 1247 - 1255
• Main Authors: Aizawa, Rihito, Takayama, Kenji, Nakamura, Kiyonao, Inoue, Takahiro, Yamasaki, Toshinari, Kobayashi, Takashi, Akamatsu, Shusuke, Ogawa, Osamu, Mizowaki, Takashi
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01.10.2019; Springer Nature B.V
• Subjects: Androgens; Cancer Research; Medicine; Medicine & Public Health; Morbidity; Oncology; Original; Original Article; Patients; Prostate cancer; Prostate-specific antigen; Radiation therapy; Rectum; Surgical Oncology; Survival; Intensity-modulated radiation therapy; Early salvage androgen deprivation therapy; Short-term androgen deprivation therapy; Prostate cancer; Unfavorable risk
• ISSN: 1341-9625; 1437-7772
• DOI: 10.1007/s10147-019-01478-y

Background The optimal timing of salvage androgen deprivation therapy (ADT) following definitive radiation therapy for prostate cancer (PCa) is unknown. This study evaluated the efficacy of early initiation of salvage-ADT (S-ADT) based on predetermined timing among patients with unfavorable PCa treated with high-dose intensity-modulated radiation therapy (IMRT). Materials and methods High-risk (HR) and very-high-risk (VHR) PCa patients treated with IMRT at our institution between September 2000 and December 2010 were analyzed retrospectively. Treatment consisted of high-dose IMRT (78 Gy/39 fractions) combined with 6 months of neoadjuvant-ADT (NA-ADT). S-ADT was initiated when prostate-specific antigen levels exceeded 4.0 ng/mL. Results In total, 268 (184 HR and 84 VHR) patients were analyzed. The median follow-up period was 114.4 months. The 10-year overall survival (OS), PCa-specific survival (PCSS), biochemical failure (BF), and clinical failure (CF) rates were 82.8%, 97.1%, 27.3%, and 12.8% among the HR PCa patients and 79.4%, 87.9%, 56.2%, and 26.7% among the VHR PCa patients ( p  = 0.839, = 0.0377, < 0.001, and < 0.001), respectively. The 10-year cumulative incidence rates of urinary and rectal (grades 2–3) toxicities were 22.6% and 5.8%, respectively. No grade 4 or higher toxicities were observed. Conclusion High-dose IMRT combined with short-term NA-ADT resulted in long-term disease-free status, with acceptable morbidity among approximately three-fourths of the HR PCa patients and nearly half of the VHR PCa patients. Moreover, excellent survival outcomes were achieved by the early S-ADT initiation. This approach may be a promising alternative to uniform provision of long-term ADT.